It was an accident waiting to happen. A huge hole on the floorboard of a bus of Zion Matriculation School — located in Chennai suburb Tambaram — was kept covered with a piece of cardboard.

It was an accident waiting to happen. A huge hole on the floorboard of a bus of Zion Matriculation School — located in Chennai suburb Tambaram — was kept covered with a piece of cardboard.

On Wednesday, seven-year-old Shruti, a student of class 2, stepped on the cardboard. She fell and was crushed under the rear wheels.

To make matters worse, the bus driver and conductor remained oblivious. The bus had travelled about half a kilometer before the locals, who gave chase, caught up with it.

When they confronted the driver, he insisted such a thing was impossible. The angry mob thrashed him and set the bus on fire.

The incident occurred around 3.30 pm at Mudichur area of Tambaram, when the bus was dropping the children home.

"I was filling petrol in my scooter when I saw the girl fall and get crushed," said Vijayan, an eyewitness, who was among the people who chased the bus.

While the driver has been arrested, the school authorities have rushed to deny any responsibility in the matter.

"The vehicle is not owned by the school. It was hired from a private operator," said K Vijayan, administration-in-charge of the school. "The condition of the bus is the contractor’s responsibility."

KL Sivakumar, a member of the Parent-Teachers Association, however, said nowhere on the bus was it written that it was ‘On Contract’. "In fact, the bus had the name of the school painted on its panels. The school charges Rs. 7,000 every term as bus fees and must be responsible for the children’s safety," he said.

The police are probing the matter.

"After investigation, the responsibility for the safety aspects would be fixed," said S Manoharan, SP, Kancheepuram.